FAQ: Brown Patches on Lawns

Brown patches on lawns are a source of untold annoyance to gardeners. Aside of being so unsightly, the biggest headache with them is that there are so many different causes – which makes curing the problem very difficult.

However, as any fan of CSI or Sherlock Holmes will be aware, if you look carefully enough, you’ll find that there are often clues to be found.

Why Does the Lawn Go Brown After I Mow?

There are two common causes of this – and both are to do with lawn mower maintenance.

If the patches are largely confined to the area around the tips of the grass – something which, for obvious reasons, tends to be most noticeable on fine quality lawns – and you’re using a rotary or hover mower, then it’s probably caused by dull blades. If they’re not sharp enough, then instead of cutting cleanly, the grass gets torn and bruised – leading to browning.

An incorrectly aligned base plate on a cylinder mower can have much the same effect. In either case, fix the problem and your brown patches should soon disappear.

The second cause applies to lawns where petrol mowers are used – and the giveaway sign is a single patch which extends right down to the base of the grass stems, appearing suddenly a few days after mowing. It’s usually caused by spilt petrol or engine oil, mostly when the mower is refilled, although a leak can sometimes produce the same effect. If this is behind your patch, then simply remembering not to refuel and oil your mower on the grass should see the problem banished once and for all.

I’ve Got A Really Thin Lawn, Covered In Yellowish Patches And Full Of Moss. Can Anything Be Done?

The presence of moss is the real pointer to the most likely problem, namely compaction. It’s surprisingly common in areas with heavy soils – particularly clays – and especially with lawns that see a lot of use.

Treatment principally involves aeration and improving the drainage – which may call for installing specialist soil drains in severe cases.

My Lawn Has Suddenly Developed Brown Stripes; What’s Going On?”

One possible cause would be a poorly maintained lawn mower which is bruising the grass, while the other most common reason for this is overdosing with fertilizer, which can tend to scorch the grass. If the browning appeared shortly after a weed-and-feed session, then you need to check that you’re using the recommended dose rate and water-in fertilizer if it hasn’t rained within a couple of days of the original application.

Why Have I Got Brown Patches Inside Rings of Emerald Green Grass?

Do you have a dog – or more accurately – a bitch? A patch of scorched grass edged with a ring of lush, green grass is a classic sign of the aftermath of bitch urine. Since the poor thing has to “go” somewhere, if you can’t encourage her to perform in a part of the garden where the rings won’t matter too much, the only solution is to follow her round with a watering can and dilute her urine once she’s “been.”

It’s not a problem for all dog owners – some bitches just seem to produce more scorching urine than others.

My Newly Laid Lawn Has Developed Irregular Brown Patches; It Used To Be Perfect And Was Really Doing Well. What Should I Do?

This is a common problem of newly-built houses, where unfortunately from the gardener’s perspective all manner of rubble and rubbish often gets buried beneath the soil. Buried debris alters the water holding characteristics of the ground and can often create localised areas of almost permanent drought, no matter how religiously you water your lawn.

The only solution if you think this is the problem, is to roll back the turf and have a look. If you can locate and remove the offending items and fill in the void with a suitable grade of soil or compost, your new lawn should soon be well on the way to recovery.

Irritating though brown patches are, they are the outward sign that all is not well with your lawn and that something needs to be done. Whether it’s pests, disease or maintenance issues that are behind the problem, if you look carefully, the clues will be there and, as always, working out what’s wrong is a big step towards putting things right.

Used electric mower in the past, no issues. but since using petrol mower. I have noticed the lawn turns brown all around the area. Its not in little patches but just generally all over the lawn. last cut was in october now the grass has started to grow but I still have areas of brown and the lawn doesnt look really nice compared to the other lawns in the area. I am not sure what is happening. I tried to use evergreen but still the grass looks brown.

RAM - 10-Mar-17 @ 11:18 PM

I live in Illinois. The past 2 years when it gets noticeably more dry as summer goes on my lawn has developed a powdery orange substance on the grass. By the time I finish mowing, my shoes are orange. Is this some sort of a fungus? The lawn seems to be healthy and relatively weed free. I apply fertilizer and weed control regularly according to the manufacturers specifications. Any suggestions?

Russ - 23-Jul-14 @ 2:18 AM

Our front lawn was lifted and well dug over before the gardener laid topsoil. He 'said' at the time, that the soil had manure included but I doubted it at the time as firstly, looked a tan colour rather than dark and also no smell. He laid the lawn which realy was good quality and a lovely green. We watered well. Since then a number of brown patches have and are appearing. He said that is thatching. He has returned and put some soil lightly on top of the worst patches and some quick growing seed. Not sure I am happy and also, surely this is treating the sympton not the cause?